Tarandus
, , , , , , | abbreviation = Tar | genitive = Tarandi | pronounce = Tü•ran•dis | symbolism = The | dino = Kuhudtij | dinoabbrev = Kuh | dinogen = Kuhudta | dinopronounce = Ku•hud•tij | mRA = | mdec= | ndec = | sdec = | wRA = | eRA = | quadrant = NQ4 | bordering = Avis Chtapodi Noctua Simianus Solarium Testudo | area = 4296.386 sq. deg. (6th) | proportion = 104.147‰ | average = 613.769 sq. deg. (3rd) | namedstars = 41 | mainstars = 4 | nakedeyestars = 396 | bfstars = 449 | ehstars = 47 | brightstars = 18 | brighteststar = (0.77 ) | nearbystars = 28 | neareststar = (1.83 , 5.98 ) | messierobjects = 28 | fullrange = 44°N–38°S | partialrange = 90°N–44°N, 38°S–90°S | date = July 5 | solarzodiac = 12/1–2/15 | tropicalzodiac = 11/23–1/19 | siderealzodiac = 12/16–2/14 }} Tarandus (Latin for ) is a caelregio with midpoint located in fourth quadrant of the northern hemisphere. However, the area of Tarandus south of the equator is very slightly more than in the northern hemisphere. The reason why this midpoint lies in the northern hemisphere instead of southern hemisphere is because the northernmost border is further away from the than the southernmost border. This caelregio can also be called Rangifer since Rangifer also means reindeer in Latin. The and cross this caelregio. Tarandus is composed of seven s (the list is at the top of the infobox to the right), including , , , and . Tarandus covers about 104‰ of the sky with an area of 4296 square degrees. This caelregio was named after the , which was located between the constellations and in the neighboring caelregio Testudo. Notable stars Bright stars At a of 0.77, an is the Tarandus's brightest star, located in . Altair is one of the stars that make up the , the other two are and , both located in the neighboring caelregio Avis. The other notable bright stars in Tarandus are (a 1.80m ocated in Sagittarius), (a 2.08m A-type giant located in Ophiuchus), (a 2.83m located in Sagittarius), and (a 2.87m giant located in Capricornus). Nearby stars At a of 5.98 s, is the Tarandus's nearest star, located in Ophiuchus. Barnard's Star is a with the highest known star. Barnard's Star can sometimes be referred as Proxima Ophiuchi. This star was discovered by the American astronomer in 1916. Another notable nearby star is , which was claimed to have a first ever discovered in 1855, but subsequent observations gradually ruled out the planet's existence. 70 Ophiuchi is a K-type main sequence star located 16.58 light-years away. Variable stars The only notable variable star in Tarandus is (Alpha Herculis). This varies in brightness with a period between 50–150 days that is the result of irregular . Double stars and are optical doubles. The two stars of α Cap are separated by 0.11° which is resolvable with the . α1 is nearly five and a half times further away from the observer than α2, 174 vs. 32 light-years. The two stars of ξ Sgr are separated by 0.46° which is more easily resolvable with the naked eye. ξ2 is nearly 52/3 times further away from the observer than ξ1, 2069 vs. 365 light-years. Planetary systems As of April 2011, there are 47 known s in Tarandus. The notable example is in Hercules, which has a (P170) in a circular orbit. HD 154345 also contain six hypothetical planets, four of them are . Also in Hercules, has a long-period saturnian planet named Diomedes (P182) along with two hypothetical planets closer to the star: Tydeus and Deipyle. Yet another planetary system in Hercules is , which has two long-period planets: (P21) and (P163). 14 Her also has two hypothetical planets orbiting closer than the two known planets, respectively named Antimache and Mycenae. Mycenae is in a 1:4 with Cerenytis while Cerenytis is in a 1:4 resonance with Eurystheus. So this puts three outer planets in a 1:4:16 , which would dynamically make 14 Her a very interesting planetary system. But the most famous example of a planetary system in Tarandus is in Ophiuchus, which has the super-Earth exoplanet detected by . This planet, named (P384), maybe be an surrounded by a thin layer of water vapor or thick layer of high clouds. Despite this planet has a relatively cool temperature of 516 K compared with all other transiting exoplanets, it orbits closest to the star than any other exoplanets. The planet's distance from the star is only 1/70 the Earth–Sun distance and it takes 1.58 days to orbit the star. The reason why this planet is so cool is because the parent star's radiation is only about 1/300 as strong as the . Another star with a transiting planet is (located in Hercules), which has a planet named (P151). Based on its density, the core makes up merely 70% the mass of this planet. The mass of this planet is 0.36 and the density 0.81 g/cm3. Notable deep sky objects Tarandus contains a lot of notable deep sky objects. The ( 8), which is an , and , which is an , are located in Sagittarius. The (M17, also known as the Swan Nebula) is an H II region also located in Sagittarius. Also in this constellation, there is , which is a at the center of . There is the (M24). This star cloud does contain the open cluster . Sagittarius also contains the neareast (NGC 6822) located just 1.6 million light-years from the Milky Way. This galaxy is similar in structure and composition to the (SMC). The ( 2-9) is a located in Ophiuchus. There is the (M13), which is a bright visible to the in Hercules. There is a globular cluster in Sagittarius: , which is the first known globular cluster discovered in 1665 (possibly earlier). This globular cluster is the third brightest in the sky after and and before M13 just mentioned. This cluster is even more notable because it contains a planetary nebula. Sagittarius contains another globular cluster: . This cluster appears more grainy than nebulous, which is more akin to an open cluster than a globular cluster. In Capricornus, there is the globular cluster . In , there is the (M11), which is one of the densest s containing at least 3000 stars within a 23 light-year diameter. In Vulpecula, it contains the (M27), which is a . Ophiuchus contains the Kepler's located in our galaxy after the progenitor star exploded in 1604. This supernova was seen by . It was the first naked-eye supernova since 1572 and the next naked-eye supernova would not take place until 1987. Gallery Visibility In the northern hemisphere, Tarandus can be visible from late fall till mid winter. Since the area of Tarandus is extremely similar between northern and southern hemispheres, observers at the and would see about the same area of Tarandus. The north pole observer would find that the northern half of Tarandus appears to circumnavigate clockwise along the horizon, but the southern half would never be visible. The south pole observer would see that the southern half of Tarandus appears to circumnavigate counterclockwise along the horizon, but the northern half would never be visible. Sagittarius contains the "Teapot" which the main stars make up the prominent arrow we see in the sky. Zodiac In 2011, the appears to cross Tarandus from December 1 till February 15; it crosses the constellations Ophiuchus (December 1 till December 17), Sagittarius (December 18 till January 18), and then Capricornus (January 19 till February 15). This zodiacal caelregio is located between Simianus to the west and Chtapodi to the east. Category:Articles Category:Caelregios